A string inverter is a device used in solar energy systems to convert direct current (DC) generated by solar panels into alternating current (AC) that can be used in homes or fed into the electrical grid. It connects multiple solar panels in a series, or "string," allowing them to work together efficiently. String inverters are popular due to their simplicity and cost-effectiveness. They are typically installed on rooftops or near the solar panel array, making them accessible for maintenance. However, their performance can be affected by shading or dirt on individual panels, which may reduce overall energy output.